CN113874799B - NC program generation system and NC program generation method - Google Patents
NC program generation system and NC program generation method Download PDFInfo
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- CN113874799B CN113874799B CN202080038797.8A CN202080038797A CN113874799B CN 113874799 B CN113874799 B CN 113874799B CN 202080038797 A CN202080038797 A CN 202080038797A CN 113874799 B CN113874799 B CN 113874799B
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- 238000005520 cutting process Methods 0.000 description 40
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q15/00—Automatic control or regulation of feed movement, cutting velocity or position of tool or work
- B23Q15/007—Automatic control or regulation of feed movement, cutting velocity or position of tool or work while the tool acts upon the workpiece
- B23Q15/12—Adaptive control, i.e. adjusting itself to have a performance which is optimum according to a preassigned criterion
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/404—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/4093—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by part programming, e.g. entry of geometrical information as taken from a technical drawing, combining this with machining and material information to obtain control information, named part programme, for the NC machine
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q15/00—Automatic control or regulation of feed movement, cutting velocity or position of tool or work
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/4093—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by part programming, e.g. entry of geometrical information as taken from a technical drawing, combining this with machining and material information to obtain control information, named part programme, for the NC machine
- G05B19/40937—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by part programming, e.g. entry of geometrical information as taken from a technical drawing, combining this with machining and material information to obtain control information, named part programme, for the NC machine concerning programming of machining or material parameters, pocket machining
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/36—Nc in input of data, input key till input tape
- G05B2219/36186—Programming languages for lathe, mill or general use mixed
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/36—Nc in input of data, input key till input tape
- G05B2219/36204—Lathe, turning
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/45—Nc applications
- G05B2219/45156—Grind on lathe
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Human Computer Interaction (AREA)
- Manufacturing & Machinery (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Geometry (AREA)
- Mechanical Engineering (AREA)
- Numerical Control (AREA)
- Turning (AREA)
Abstract
Provided is a technique for generating an NC program capable of ensuring proper machining accuracy. In a computer (10) for converting NC programs for turning work of a workpiece in a lathe, the CPU (11) is configured to calculate displacement occurring in the workpiece of a processing object at a plurality of processing positions during turning work, determine a movement path of a tool used during turning work according to the displacement occurring in the workpiece at the plurality of processing positions, and generate an NC program for causing the tool to move according to the determined movement path.
Description
Technical Field
The present invention relates to a technique for generating an Numerical Control (NC) program for NC.
Background
In recent years, turning of a workpiece (hereinafter, sometimes referred to as a workpiece) is sometimes performed by inputting an NC program into a lathe corresponding to NC.
For example, patent document 1 discloses "providing a tool deformation amount correction method for correcting a deformation amount of a tool and performing machining, which is characterized by comprising: a memory for storing tool deformation parameters for calculating the tool deformation; a preprocessing operation unit for reading the processing program and outputting the processing conditions; a tool deformation amount calculation unit that calculates a tool deformation amount from the tool deformation parameter and the machining condition; a tool correction unit that calculates a tool correction amount; an adder for adding the tool deformation amount and the tool correction amount to a movement command to determine a movement amount; and an interpolation unit that interpolates the movement amount.
Prior art literature
Patent document 1: japanese patent laid-open No. 4-52908
Disclosure of Invention
In the field of producing products by processing workpieces, improvement in the processing accuracy of the products is demanded.
In the technique disclosed in patent document 1, the machining accuracy is improved by correcting the tool deformation amount. However, in the correction of the tool deformation amount, there are cases where the improvement effect of the machining accuracy is small.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique for generating an NC program capable of ensuring proper machining accuracy.
An NC program generating system according to one aspect is achieved by focusing on that a main cause of a machining error of a product in turning such as turning for an elongated workpiece is deformation of the workpiece. An NC program generating system according to one aspect is an NC program generating system including a processor for generating an NC program for turning a workpiece in a lathe, wherein the processor calculates displacements occurring in the workpiece to be processed at a plurality of machining positions during turning, determines a movement path of a tool used during turning from the displacements occurring in the workpiece at the plurality of machining positions, and generates the NC program for causing the tool to move in accordance with the determined movement path.
According to the present invention, an NC program capable of ensuring proper machining accuracy can be generated.
Drawings
Fig. 1 is an overall configuration diagram of a processing system according to embodiment 1.
Fig. 2 is a block diagram of a conversion computer according to embodiment 1.
Fig. 3 is a functional configuration diagram of the conversion computer according to embodiment 1.
Fig. 4 is a flowchart of NC program conversion processing according to embodiment 1.
Fig. 5 is a diagram showing a state of turning according to the comparative example.
Fig. 6 is a diagram showing a state of turning according to example 1.
Fig. 7 is a diagram showing an example of a relationship between a rotation axis of a lathe and a movement axis of a tool table.
Fig. 8 is a graph showing experimental results of diameter errors caused by turning of example 1 and comparative example.
Fig. 9 is a diagram illustrating values related to turning of a workpiece.
Fig. 10 is a diagram illustrating rough machining and finish machining according to example 4.
(symbol description)
1: a workpiece; 2: a lathe; 3: a tool; 5: a network; 10: a conversion computer; 11: a CPU;12: a network interface; 13: a user interface; 14: storing the resource; 21: a main shaft; 22: a tool holder; 23: a tailstock; 25: a tool table; 26: a control device; 100: a processing system.
Detailed Description
Embodiments are described with reference to the drawings. The embodiments described below do not limit the invention according to the claims, and many elements and all combinations thereof described in the embodiments are not necessarily essential to the solving means of the invention.
Example 1
< System Structure >
Fig. 1 is an overall configuration diagram of a processing system according to embodiment 1.
The machining processing system 100 includes a conversion computer 10, a lathe 2, and an in-situ computer 30 as an example of an NC program generating system. The conversion computer 10, the lathe 2, and the site computer 30 are connected via the network 5. The network 5 may be either a wired network or a wireless network. The lathe 2 and the field computer 30 may be disposed in the same place, for example.
The conversion computer 10 executes, for example, the following processing: NC programs for turning with higher machining accuracy (corrected NC programs) are generated from NC programs (pre-correction NC programs) generated by CAM (Computer Aided Manufacturing) and computer-aided manufacturing. The details of the conversion computer 10 will be described later.
The lathe 2 includes a spindle 21, a fixing jig 22, a tailstock 23, a vibration-proof frame 24, a tool table 25 as an example of a tool fixing portion, and a control device 26.
The main shaft 21 rotatably supports the fixing jig 22. The fixing jig 22 is a jig for fixing the workpiece 1, typically a chuck. The fixing jig 22 may be a fixing jig using a bolt, a magnet, or the like, and may be a structure capable of fixing the workpiece 1 to the main shaft 21. With this structure, the workpiece 1 is rotatably fixed to the spindle 21 of the lathe 2 via the fixing jig 22.
Tailstock 23 is disposed at a position facing spindle 21 on rotation axis O of spindle 21. The tailstock 23 contacts an end surface of the workpiece 1 fixed to the spindle 21 by the fixing jig 22 on the opposite side of the end surface of the spindle 21 side, and rotatably fixes the workpiece 1. The vibration isolator 24 supports the side surface of the workpiece 1 to prevent the workpiece 1 from vibrating during turning. According to the vibration isolator 24, a workpiece having low rigidity can be appropriately machined, and the machining accuracy of turning can be improved.
The tool table 25 holds the tools 3. The tool table 25 is, for example, a turntable, and a plurality of tools can be fixed, and the tools used for machining can be selected by rotating the tool table 25. The tool table 25 may be a structure that allows exchange between tools stored in the tool magazine and tools fixed to the tool table 25 by an ATC (Automatic Tool Changer, automatic tool changing system) device, not shown, or may be a structure that allows manual attachment of tools. The tool table 25 may be configured to have a rotary spindle and to be capable of mounting a rotary tool such as a drill. The tool table 25 can be moved by a driving mechanism (not shown) in the direction of the rotation axis O (strictly speaking, the direction is not uniform due to an error) and the radial direction of the rotation axis O (strictly speaking, the direction is not uniform due to an error) by the control of the control device 26.
The tool 3 may also comprise an integrated cutter with a cutting edge, an insert with a cutting edge and a cutter for mounting the insert, a holder for fixing these cutters to the tool table 25.
The control device 26 reads an NC program stored in a recording device (not shown) provided inside, and controls the operations of the workpiece and the tool based on various factors (machining speed, feed speed) and a machining path (moving path) of machining described in the NC program, thereby controlling turning. The NC program may be data in which the operation of the lathe is described in the form of a G code or the like, or data in which various factors of machining such as a machining path and a rotational speed, and the operation of the lathe are described in the form of, for example, CL (Cutter position) data, which cannot directly control the operation of the lathe. The control device 26 may have a machining path generation function of generating a machining path (moving path) according to a machining shape and machining conditions.
In addition, the lathe 2 may be turned in a so-called cantilever state without the tailstock 23 and without fixing the end on the opposite side to the spindle 21 of the workpiece 1. In a lathe having a spindle on both sides, the tailstock 23 may not be provided, and the end portion on the opposite side of the workpiece 1 may be rotatably fixed to the other spindle via a fixing jig connected to the spindle. The lathe 2 may not include the vibration isolation mount 24.
Next, the conversion computer 10 will be described in detail.
Fig. 2 is a block diagram of a conversion computer according to embodiment 1.
Hardware
As an example, the conversion computer 10 is a personal computer or a general-purpose computer. The conversion computer 10 includes a CPU11 as an example of a processor, a network interface 12 (abbreviated as network I/F in the figure), a user interface 13 (abbreviated as user I/F in the figure), a storage resource 14 as an example of a storage section, and an internal network connecting these constituent elements.
The CPU11 can execute programs stored in the storage resources 14. The storage resource 14 stores a program to be executed by the CPU11, various information used in the program, an NC program used in the lathe 2, and the like. The storage resource 14 may be, for example, a semiconductor memory, a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like, or may be a volatile type memory, or may be a nonvolatile type memory.
The network interface 12 is an interface for communicating with external devices (for example, the control device 26 of the lathe 2, the field computer 30, and the like) via the network 5.
The user interface 13 is, for example, a touch panel, a display, a keyboard, a mouse, or the like, and may be any other device as long as it can receive an operation from a worker (user) and display information. The user interface 13 may also be constituted by these multiple devices.
< data, etc. >)
The storage resource 14 stores a conversion program 1411, a configuration information acquisition program 1412, lathe configuration information 1413, tool information 1414, workpiece information 1415, a NC program before correction 1416, and a NC program after correction 1417. The storage resource 14 may store information other than the above. Each data and program will be described in detail in the following paragraphs. In addition, each piece of information or a part of items of each piece of information may be omitted.
* Lathe structure information 1413. The lathe structure information 1413 is configured as a table storing information on the lathe 2, for example. The lathe structure information 1413 includes the following respective information.
(a1) An identifier of lathe 2 (lathe ID). As the lathe ID, an identifier or a network address of the control device 26 may be substituted.
(a2) The model of the lathe 2.
(a3) The installation place of the lathe 2.
(a4) The actual data of the lathe 2, such as the time of use.
(a5) The temperature of a predetermined portion of the lathe 2. The predetermined portion may be the spindle 21 of the lathe 20.
(a6) Information about the rigidity of a predetermined portion of the lathe 2 (for example, young's modulus of the portion, bending amount, and the like). The predetermined portion may be the spindle 21 or the tool table 25 of the lathe 2.
(a7) The shape of a predetermined portion of the lathe 2. The shape of the predetermined portion may be the length of the spindle 21 of the lathe 2 or the shape of the tool table 25.
(a8) Offset values set in accordance with the environment of the aged and installed. The offset value is a value used for fine correction of coordinates when a tool in the NC program moves, and is used for correction of a situation such as a slight inclination of the table due to aged deterioration, for example.
(a9) Manufacturer, model, etc. of the control device 26. The control device 26 may determine such a situation by slightly varying the description form of the NC program depending on the manufacturer and model.
(a10) The vibration of the components such as the spindle 21 and the tool table 25, the movement accuracy (for example, the backlash amount of the tool table), the straightness, the flatness, the parallel movement, the vibration amplitude and the vibration frequency when the device is operated.
In the present embodiment, the information about (a 1), (a 2), (a 4), (a 5), (a 8), and (a 9) is acquired from, for example, the control device 26 (or the field computer 30) of the lathe 2, and the information about (a 3), (a 6), (a 7), and (a 10) is acquired from the input information inputted by the user. The method of acquiring information is not limited to this, and at least a part of (a 1), (a 2), (a 4), (a 5), (a 8), and (a 9) may be acquired from input information input by the user via the user interface 13, and information acquired from the control device 26 (or the field computer 30) among (a 3), (a 6), (a 7), and (a 10) may be acquired from the control device 26 (or the field computer 30). The information acquired from the control device 26 (or the site computer 30) may be acquired from an alternative device (for example, another computer or the sensor itself).
* The tool information 1414 is information on each tool 3. The tool information 1414 includes the following information.
(b1) An identifier of the tool 3 (tool ID: e.g. serial number, etc.). As the identifier of the tool 3, it may be automatically given by the CPU11 executing the structure information acquiring program 1412.
(b2) Model of tool 3.
(b3) Regarding the material, shape, mechanical material properties (young's modulus, poisson's ratio, transverse modulus of elasticity, etc.), use history, temperature, etc. of the tool 3. Here, since the rigidity varies depending on the material and shape of the tool 3, these pieces of information are also pieces of information concerning the rigidity. Unless specifically noted, the term "shape" includes representative values obtained from the shape, such as the length of the tool 3 protruding from the tool table 25 (protruding length) and the straightness of the tool 3 when the tool 3 is attached to the tool table 25, in addition to the three-dimensional shape and the cross-sectional shape shown in the general drawings and CAD data.
In the present embodiment, the information about (b 1) to (b 3) is obtained from, for example, input information inputted by the user via the user interface 13, but the information that can be obtained from the control device 26 (or the field computer 30) may be obtained from the control device 26 (or the field computer 30).
* Workpiece information 1415. The workpiece information 1415 is, for example, information such as shape data before machining of the workpiece 1, a material, mechanical material characteristic stiffness (young's modulus, poisson's ratio, transverse elastic modulus, etc.), machining target shape data of the workpiece 1, and the like. The machining target shape data is data representing a shape that is a target for machining by the NC program. In the case of machining the workpiece 1 into the target shape, this means that the error is zero. The workpiece information 1415 may be obtained from the control device 26 (or the site computer 30) or may be obtained from input information input by a user via the user interface 13.
* The NC program before correction 1416 is an NC program created by CAM for use in a lathe. The NC program before correction 1416 is generated and transmitted by a computer not shown and provided with a CAM.
* The corrected NC program 1417 is an NC program obtained by converting the NC program 1416 before correction so as to match the turning work for a specific workpiece in the lathe 2. In addition, when the conversion processing is not performed on any pre-correction NC program 1416, there is no post-correction NC program 1417.
< program for operation in conversion computer >
< transform 1411>
The conversion program 1411 executes the following processing by being executed by the CPU 11.
* The conversion program 1411 executes processing for generating a corrected NC program 1417 from the pre-correction NC program 1416. Further, details of the processing will be described later.
Structure information acquiring program 1412-
The configuration information acquisition program 1412 executes the following processing by being executed by the CPU 11.
* The configuration information acquisition program 1412 acquires various information about the lathe 2 from the control device 26 of the lathe 2. The information obtained includes the information (a 1), (a 2), (a 4), (a 5), (a 8), and (a 9).
* The configuration information acquisition program 1412 acquires various information from the user (information ((a 3), (a 6), (a 7), and (a 10)) related to the lathe 2 and information ((b 1) to (b 3)) of the tool information 1414 acquired from the user via the user interface 13.
Next, the functional configuration of the conversion computer 10 will be described.
Fig. 3 is a functional configuration diagram of the conversion computer according to embodiment 1.
The conversion computer 10 includes an input unit 41, a bending calculation unit 42, and a machining path determination unit 43. In the present embodiment, the input unit 41 is configured by the CPU11 executing the configuration information acquisition program 1412, and the bending operation unit 42 and the machining path determination unit 43 are configured by the CPU11 executing the conversion program 1411.
The input unit 41 inputs the shape of the workpiece, the mechanical material properties of the workpiece, and the rigidity of a portion (the spindle 21 and the fixing jig 22, which are examples of the fixing portion, and referred to as a workpiece fixing portion) where the workpiece is fixed in the lathe 2 for machining the workpiece. The input unit 41 inputs the NC program 1416 before correction.
Here, the shape of the workpiece may be a shape (raw material shape) of the workpiece before processing or a target shape of the workpiece after processing. In addition, the mechanical material properties of the workpiece include at least the Young's modulus of the material of the workpiece. Poisson's ratio or transverse modulus of elasticity may also be included in the mechanical material properties. The stiffness of the workpiece fixture includes a translational spring rate and a rotational spring rate in the workpiece fixture. Here, the translational spring coefficient is the reciprocal of the displacement for the unit load, and the rotational spring coefficient is the reciprocal of the bending angle for the unit moment. The translational spring constant and the rotational spring constant may be determined in advance by analysis or measurement, and the determined coefficients may be used.
The bending calculation unit 42 calculates displacement occurring for the workpiece at a plurality of processing positions. Here, the displacement generated with respect to the workpiece includes displacement caused by bending of the workpiece and bending of the workpiece fixing portion to which the workpiece is attached. Further, since the rigidity of the workpiece fixing portion is higher than the rigidity of the workpiece, the latter displacement may not be included in the displacement generated with respect to the workpiece, as the case may be. Since the workpiece to be turned is generally rotationally symmetrical, the workpiece can be modeled as a stepped beam, and the bending of the workpiece can be calculated using the finite element of the beam. Specifically, the bending calculation unit 42 analyzes the machining path before correction, that is, the machining path in which the bending of the workpiece is not considered, and determines a plurality of machining positions. Here, the machining path before correction can be determined based on the instruction (block) of the NC program 1416 before correction. In the control device 26, when a machining path is generated according to the target shape of the workpiece, the generated machining path may be used.
Regarding displacement at a certain machining position (object machining position), if after dividing the step beam model of the workpiece at the object machining position and setting the nodes, cutting force in turning is provided as a shearing load and rigidity of the workpiece fixing portion is solved as a boundary condition, the displacement can be calculated. The shape of the workpiece used as the step beam model is preferably a shape (intermediate shape) when the portion interfering with the tool is successively removed based on the material shape and reaches the target machining position, but may be a material shape or a target shape after machining. The cutting force is preferably calculated by analyzing the volume, cross-sectional area, and cutting of the removal region at the target machining position, but may be obtained from set machining conditions such as cutting and feeding, or the cutting force measured at the time of actual machining may be used.
The machining path determining unit 43 determines an appropriate machining path using the calculated displacement. When a workpiece is displaced during processing due to deformation or the like caused by bending, the processing amount changes, and the diameter of the processed workpiece deviates from a target value. Therefore, when the workpiece is displaced away from the tool 3, since the diameter of the workpiece after the machining becomes larger than the target value, the machining path determining section 43 determines the corrected machining path as follows: the cutting by the tool 3 is increased by bringing the machining path closer to the workpiece, and the diameter of the workpiece is set to be a target diameter in a state where the workpiece is displaced. In addition, when the workpiece is displaced so as to approach the tool 3, since the diameter of the workpiece after the processing becomes smaller than the target value, the processing path determining section 43 determines the corrected processing path as follows: the cutting by the tool 3 is reduced by moving the machining path away from the workpiece, and the diameter of the workpiece is set to be the target diameter in a state where the workpiece is displaced. In addition, regarding the corrected machining path, the position coordinates of the NC program 1416 before correction may be edited to new position coordinates after correction, or the position coordinates of the NC program 1416 before correction may be used as they are, and the tool offset value may be changed according to the difference between the position coordinates before correction and the position coordinates after correction. For example, when the tool offset is changed using the position coordinates of the NC program 1416 before correction as it is, the position coordinates set by the NC program 1416 before correction are also stored in the NC program 1417 after correction, so that the confirmation operation by the user is easy, and the readability of the NC program 1417 after correction can be ensured.
Further, since the displacement (basically bending) generated in the workpiece is generally curved with respect to the rotation axis direction, the ideal machining path is also curved. Therefore, at the time of correction of the NC program, the machining path may be specified by a curve obtained by NURBS (Non-uniform rational B-spline) interpolation. The machining path may be divided into a plurality of machining paths described in a module of the NC program, and may be an approximate polygonal line path obtained by linear interpolation or an approximate multi-arc path obtained by arc interpolation. For example, when the machining path is corrected by changing the tool offset, it is preferable to set an approximate polygonal line path obtained by linear interpolation. In addition, in the case where the processing path is generated in the control device 26 according to the shape of the workpiece, the processing path determination unit 43 may directly generate the corrected processing path in consideration of the displacement of the workpiece, instead of generating the processing path before correction.
Returning to the explanation of fig. 1, the field computer 30 will be described.
As an example, the field computer 30 is a personal computer or a general-purpose computer. The field computer 30 includes a CPU as an example of a processor, a network interface, a user interface, a storage resource as an example of a storage section, and an internal network connecting these constituent elements.
The storage resources of the onsite computer 30 store client programs. The storage resource may store the NC program before correction.
< client program >
The client program executes the following processing by being executed by the CPU.
* The client program instructs the conversion computer 10 to convert the NC program, receives the corrected NC program from the conversion computer 10, and stores the corrected NC program in the storage resource of the field computer 30 or in the recording device of the control device 26.
* The client program may read the NC program before correction instructed by the user from the storage resource and send the NC program to the conversion computer 10.
* Regarding the information input from the user via the user interface 13 to the conversion computer 10, the information input from the control device 26 by the user, or the like, the client program may be received from the user of the field computer 30 instead and transmitted to the conversion computer 10.
Next, the processing operation of the conversion computer 10 will be described.
(process 1) the configuration information acquisition program 1412 (strictly speaking, the CPU11 executing the configuration information acquisition program 1412) acquires various pieces of information (for example, (a 1), (a 2), (a 4), (a 5), (a 8), and (a 9)) on the lathe 2, which are available, from the control device 26 of the lathe 2 connected via the network 5. It is not necessary to perform the present process every time the processes 2 and subsequent processes described below are performed.
(process 2) next, the configuration information acquisition program 1412 receives a designation of the NC program 1416 before correction, which is a conversion target, from the operator via the user interface 13. The structure information acquisition program 1412 receives various information ((a 3), (a 6), (a 7), and (a 10)) related to the lathe 2, information ((b 1) to (b 3)) related to the tool used in the lathe 2, shape data, material, mechanical material characteristic stiffness (young's modulus, poisson's ratio, transverse elastic modulus, etc.) of the workpiece 1 before machining used in the lathe 2, and input (direct input or selective input) of information such as machining target shape data of the workpiece 1.
(process 3) when receiving a conversion instruction of the NC program from the user via the user interface 13, the configuration information acquisition program 1412 transmits a conversion start instruction to the conversion program 1411. Here, the conversion start instruction includes various information input (direct input or selection input) via the user interface 13.
(processing 4) when the conversion program 1411 receives the conversion start instruction, it reads the designated NC program before correction 1416, executes conversion processing for converting the NC program before correction 1416 into the NC program after correction 1417, and stores the NC program after correction 1417 generated by the conversion in the storage resource 14.
(process 5) next, the conversion program 1411 transmits the corrected NC program 1417 stored in the memory resource 14 to the control device 26 of the lathe 2.
After that, the control device 26 of the lathe 2 performs the corrected NC program 1417 after fixing the workpiece 1 to the lathe 2, thereby performing turning processing for the workpiece 1.
< concrete example of transformation processing by transformation program >
Next, a specific example of the processing operation of the conversion computer 10 will be described.
Fig. 4 is a flowchart of a transformation process according to an embodiment.
First, the conversion program 1411 reads out all the blocks of the NC program 1416 before correction to be processed, for the work area of the memory in the memory resource 14 (S11). Here, the module indicates a description section including a command (address) which can be instructed 1 time to the lathe 2 in the machining process executed by the NC program 1416 before correction. More than 1 command (address) that can be indicated simultaneously is included in the module. As the address, there is, for example, an address including a code indicating the kind of the command and a parameter related to the content of the command. If the NC program 1416 before correction has a large capacity and cannot call all the modules to the operating area of the memory, the read modules may be switched according to the progress of the processing. Note that, for example, not all the blocks of the NC program 1416 before correction to be processed may be read out at once for the work area of the storage resource 14.
Next, the conversion program 1411 performs processing of loop 1 for each module read out in step S11 (steps S12 to S19). The module to be processed in the loop 1 is referred to as an object module.
In loop 1, conversion program 1411 determines whether or not the object module is a movement command in the direction of rotation axis O of spindle 21 (step S12). As a result, when the target module is not a movement command in the rotation axis O direction (step S12: no), the conversion program 1411 advances the process to the end of the loop 1 (step S19 and thereafter).
On the other hand, when the target module is a movement command in the rotation axis direction (yes in step S12), the conversion program 1411 determines whether or not the processing path of the movement command of the target module needs to be divided (step S13). For example, if the length of the machining path in the direction of the rotation axis O is equal to or greater than a predetermined value, it may be determined that the cutting is necessary.
As a result, when it is determined that the machining path of the movement instruction of the split target module is required (step S13: yes), the conversion program 1411 splits the machining path into a plurality of unit paths (step S14). Here, the number of divisions is arbitrary, and basically when the number of divisions is increased, an appropriate processing path can be determined in more detail.
On the other hand, when it is determined that the processing path of the movement instruction of the target module is not required to be divided (step S13: no), the conversion program 1411 determines the processing path of the target module as a unit path (step S15).
After determining the unit route in step S14 or step S15, the conversion program 1411 performs processing of loop 2 for each unit route (steps S16 and S17).
In loop 2, the conversion program 1411 calculates the radial displacement of the rotation axis of the workpiece at the end point of the rotation axis direction of the unit path (step S16). Next, the conversion program 1411 corrects the coordinates of the end points of the unit paths in the radial direction, and determines the corrected unit paths. Specifically, the conversion program 1411 adds the displacement calculated in step S16 to the coordinates in the radial direction at the end point of the unit path (step S17).
After the processing of loop 2 is performed on all of the plurality of unit paths divided in step S14 or the unit path determined in step S15, the conversion program 1211 skips the processing of loop 2, and determines a corrected machining path for the machining path of the target module from the corrected unit path (step S18). As a method for determining the corrected machining path, the end points of all corrected unit paths may be connected by straight lines, or approximate lines (straight lines or curved lines) based on the end points may be obtained. In the case where the correction post-processing path is set to be an approximation line, the correction post-processing path may be divided in the rotation axis direction, and the division number may be determined so that the approximation error at each point of division becomes equal to or smaller than a predetermined value.
Next, the conversion program 1411 generates a correction module (or a module group) serving as a module (or a module group) to be a corrected machining path determined in step S18, and replaces the target module of the work area with the generated correction module (or the correction module group) (step S19).
After executing the loop 1 processing for the target module, the conversion program 1411 performs the loop 1 processing with the next module as the target module, and skips the loop 1 processing when the loop 1 processing has been performed for all the modules.
Next, the conversion program 1411 stores the NC program of the work area as the corrected NC program 1417 in the storage resource 14 (step S20), and ends the processing.
According to the conversion process described above, the machining path is corrected based on the radial displacement of the rotation axis caused by the bending of the workpiece or the like, and a block corresponding to the corrected machining path is generated, so that it is possible to generate a corrected NC program capable of appropriately suppressing the influence of the displacement caused by the bending of the workpiece or the like during turning. By executing the NC program after correction, the influence of the bending of the workpiece or the like can be appropriately suppressed, and the machining accuracy of the machined product can be improved.
Next, an example of turning performed by the NC program 1416 before correction (comparative example) and an example of turning performed by the NC program 1417 after correction are specifically compared. Here, the turning is performed by turning such that a cylindrical workpiece has a constant diameter.
First, turning performed by the NC program 1416 before correction will be described.
Fig. 5 is a diagram showing a state of turning according to the comparative example. Fig. 5 (a) shows a state before cutting, fig. 5 (B) shows a state in which the tip side of the workpiece is cut, fig. 5 (C) shows a state in which the vicinity of the fixing jig for the workpiece is cut, and fig. 5 (D) shows a state after cutting is completed.
In the NC program 1416 before correction, as shown in fig. 5 (a), the machining path Pb is directed parallel to the rotation axis O toward the spindle 21.
When turning of the front end side of the workpiece 1 is started in accordance with such a machining path Pb, the workpiece 1 is displaced downward in the drawing due to the cutting force of the tool 3, as shown in fig. 5 (B).
Thereafter, when the tool 3 is moved toward the spindle 21 along the machining path Pb, the workpiece 1 is also displaced downward in the drawing in the vicinity of the fixing jig 22 as shown in fig. 5 (C). The amount of displacement of the workpiece 1 is smaller than that during cutting on the tip side.
After that, when the tool 3 is moved to the end of the machining path Pb, the turning work on the workpiece 1 is completed, and the state shown in fig. 5 (D) is set.
According to the turning performed by the NC program 1416 before correction, the cutting by the tool 3 becomes smaller as the front end portion of the workpiece 1 with a large displacement is located, so that the shape of the workpiece 1 after the cutting is completed becomes larger as the diameter of the front end portion becomes smaller as the diameter becomes closer to the fixing jig 22 as shown in fig. 5 (D). In this way, the machining accuracy of the workpiece 1 obtained by machining is poor according to the NC program 1416 before correction.
Next, turning by the corrected NC program 1417 will be described.
Fig. 6 is a diagram showing a state of turning according to example 1. Fig. 6 (a) shows a state before cutting, fig. 6 (B) shows a state in which the tip side of the workpiece is cut, fig. 6 (C) shows a state in which the vicinity of the fixing jig of the workpiece is cut, and fig. 6 (D) shows a state after cutting is completed.
In the NC program 1417 after correction, as shown in fig. 6 (a), the machining path Pa is corrected so as to be closer to the front end portion of the workpiece 1 with a large displacement, and the machining path of the tool 3 is located further down in the drawing than the machining path Pb.
When turning of the front end side of the workpiece 1 is started in accordance with such a machining path Pa, the workpiece 1 is displaced downward in the drawing by the cutting force of the tool 3 as shown in fig. 6 (B), but the machining path Pa is located lower in the drawing than the machining path Pb, so that the cutting-in becomes larger than in the case shown in fig. 5 (B).
After that, when the tool 3 is moved to the spindle 21 side along the machining path Pa, the workpiece 1 is also displaced downward in the drawing in the vicinity of the fixing jig 22 as shown in fig. 6 (C). Here, the displacement amount of the workpiece 1 is smaller than that in the cutting of the tip side, but the position of the machining path Pa is above the tip side in the drawing, and as a result, the cutting becomes substantially the same as the cutting of the tip side in fig. 6 (B).
After that, when the tool 3 is moved to the end point of the machining path Pa, the turning work on the workpiece 1 is completed, and the state shown in fig. 6 (D) is set.
According to the turning performed by the NC program 1416 after the correction, the correction amount of the machining path becomes larger as the workpiece 1 with a large displacement is located closer to the front end portion, and the correction amount of the machining path becomes smaller as the workpiece 22 with a small displacement is located closer to the fixing jig, so that the cutting by the tool 3 can be made substantially the same over the entire range in the rotation axis O direction. As a result, the shape of the workpiece 1 after cutting is completed can be made substantially the same diameter as shown in fig. 6 (D). In this way, according to the corrected NC program 1417, the machining accuracy of the workpiece 1 obtained by machining can be improved. In addition, when the displacement of the workpiece caused by the workpiece fixing portion is included in the displacement of the workpiece, deterioration of the machining precision due to the displacement of the workpiece caused by the workpiece fixing portion can be suppressed, so that the machining precision can be further improved.
< modification of example 1 >
Fig. 7 is a diagram showing an example of a relationship between a rotation axis of a lathe and a movement axis of a tool table.
In general, a small inclination error exists between the rotation axis O of the spindle 21 of the lathe 2 and the movement axis (Z axis) of the tool table 25 in the rotation axis O direction, and this inclination error becomes a factor of errors in turning. For example, between the rotation axis O and the Z axis of the workpiece 1 fixed by the fixing jig 22 and the tailstock 23, the position of the tailstock 23 moves up and down, and thus tilting occurs. In addition, as another example, in the case where the workpiece 1 is fixed only with the fixing jig 22, the spindle 21 is inclined downward due to the weight of the workpiece 1, and an inclination occurs between the spindle and the Z axis. Therefore, in the above embodiment, the inclination (inter-axis inclination) of the rotation axis O of the spindle 21 and the movement axis (Z-axis) of the tool table 25 in the rotation axis direction is measured in advance, the input unit 41 receives the inter-axis inclination (one example of angle information), the bending calculation unit 42 adds the displacement of the workpiece at the processing position to be the object to calculate the displacement of the workpiece, the displacement based on the inter-axis inclination at the processing position, and the corrected processing path is determined from the added displacement in the same manner as described above.
This reduces the influence of the inter-axis inclination during the cutting process, and improves the machining accuracy of the workpiece.
Next, experimental results of diameter errors of the workpiece 1 in the turning performed by the pre-correction NC program 1416 and the post-correction NC program 1417 are shown.
Fig. 8 is a graph showing experimental results of diameter errors caused by turning of example 1 and comparative example.
In the experiment shown in FIG. 8, a round bar (Young 'S modulus 206GPa, poisson' S ratio 0.3, diameter 50mm, length 800 mm) of S45C was used as the workpiece 1, the workpiece 1 was fixed by the fixing jig 22 for 50mm, the end face of the workpiece 1 on the opposite side to the fixing jig 22 was fixed by the tailstock 23, and the rotation speed was 650min -1 The turning process was performed by the NC program 1416 before correction and the NC program 1417 after correction, respectively, with a feed of 0.1mm/rev and a plunge of 0.1 mm. Furthermore, the inclination of the workpiece 1 is 0.016mm in the tailstock end face.
When the turning process is performed by the NC program 1416 before correction, the maximum diameter error is 0.030mm. On the other hand, when the turning process is performed by the NC program 1417 after correction in consideration of displacement such as bending of the workpiece 1, the maximum diameter error is 0.010mm. From this, it is found that the maximum diameter error in the workpiece 1 can be reduced by performing the turning processing using the corrected NC program 1417.
< action/Effect >
According to the above embodiment, the NC program before correction is converted into the NC program after correction corrected to the machining path determined according to the displacement including the bending of the workpiece at the time of machining, so that the machining accuracy of the turning work in the lathe 2 can be improved.
Example 2
Next, a conversion computer according to embodiment 2 will be described. In example 2, for convenience of explanation, the same reference numerals as those of the conversion computer according to example 1 will be used, and the explanation will be focused on the differences.
In the case where the rigidity of the tool 3 is low, the bending of the tool 3 also adversely affects the machining accuracy of the workpiece 1. For example, when the workpiece is subjected to the inner diameter processing, the protrusion of the tool 3 from the tool table 25 becomes long, and the rigidity in the radial direction of the rotation axis O becomes low. Therefore, the conversion computer according to embodiment 2 improves the machining accuracy by taking into consideration displacement such as bending of the tool 3.
Specifically, the input unit 41 receives information on the shape of the tool 3, the mechanical material properties of the tool 3, and the rigidity of the tool table 25. The bending calculation unit 42 also calculates displacement caused by bending or the like of the tool 3. As for the bending of the tool 3, as in the method of calculating the bending of the workpiece, the cutting force is provided as a shear load applied to the cutting edge portion, and the stiffness matrix is solved by using the spring coefficient in the end face of the table 25 as a boundary condition, whereby the displacement of the cutting edge can be calculated as the tool bending. Here, the relative machining error observed from the tool 3 is a result of adding the displacement of the workpiece 1 and the displacement of the tool 3. Therefore, the bending calculation unit 42 obtains a displacement obtained by adding the displacement of the workpiece 1 and the displacement of the tool 3. The machining path determining unit 43 performs the same processing as in example 1 using the displacement obtained by adding the displacement of the workpiece 1 and the displacement of the tool 3 obtained by the bending computing unit 42, and determines a corrected machining path.
According to the present embodiment, since the correction processing path can be set in consideration of the displacement of the workpiece 1 and the displacement of the tool 3, the influence of the displacement during the cutting processing can be reduced, and the processing accuracy of the workpiece can be improved.
Example 3
Next, a conversion computer according to embodiment 3 will be described. In example 3, for convenience of explanation, the same reference numerals as those of the conversion computer according to example 1 will be used, and the explanation will be focused on the differences.
For example, when the rigidity of the workpiece 1 is significantly low, if it is intended to cancel out a machining error caused by the distortion of the workpiece 1 or the like by merely changing the machining path, the amount of cutting by the tool 3 excessively increases, and there is a possibility that the workpiece 1 may be plastically deformed or broken.
Therefore, in the present embodiment, the feeding speed of the tool 3 is corrected in addition to the correction of the processing path. Specifically, the conversion program 1411 (for example, the machining path determining unit 43) corrects the feeding speed of the tool 3 so as to reduce the feeding speed of the tool 3 to the target correction amount when the correction amount of the machining path is large based on the feeding speed before correction described in the NC program 1416 before correction. This can suppress damage to the workpiece 1. In addition, when the rigidity of the workpiece 1 is sufficient, the conversion program 1411 may perform correction so as to increase the feed speed before correction, and the correction amount of the machining path may be set to a correction amount corresponding to the feed speed after correction. For example, in the case where the workpiece 1 is fixed only by the fixing jig 22 for processing, the rigidity is high in the vicinity of the fixing jig 22, so that the feeding speed can be made faster than that in the processing of the front end side of the workpiece 1.
Next, correction of the feed speed and the processing path will be described.
Fig. 9 is a diagram illustrating values related to turning of a workpiece.
The cutting force F applied to the workpiece 1 can be modeled by the following equation (1).
F＝(Kc×Vf/S+Ke)×a…(1)
Here, a is the plunge shown in fig. 9, vf is the feed speed shown in fig. 9, S is the rotation speed of the workpiece shown in fig. 9, kc is the cutting force coefficient for the cutting cross-sectional area, and Ke is the cutting force coefficient for the plunge.
If the deformation of the workpiece 1 or the like is assumed to be elastic deformation, the displacement is proportional to the cutting force F. Therefore, when the displacement δ and the target displacement δt in the NC program after correction without changing the feed speed are used, the corrected feed speed Vft is expressed by the following expression (2).
Vft＝(δt/δ)×Vf+(δt/δ-1)×(S×Ke/Kc)…(2)
Therefore, the machining path determining unit 43 determines the target displacement δt, corrects the feed speed calculated by the equation (2), corrects the machining path according to the displacement δt, and outputs a corrected NC program corresponding thereto. The feed speed Vft to be corrected may be first determined, and the displacement δt may be obtained in accordance with the relationship of expression (2).
According to the corrected NC program 1417, the excessive cutting amount can be reduced, and the machining time can be shortened.
Example 4
Next, a conversion computer according to embodiment 4 will be described. In example 4, for convenience of explanation, the same reference numerals as those of the conversion computer according to example 1 will be used, and the explanation will be focused on the differences.
Fig. 10 is a diagram illustrating rough machining and finish machining according to example 4.
For example, in the processing of the workpiece 1, rough processing may be performed to process the workpiece 1 into a shape close to the target shape, and then finish processing may be performed to process the workpiece into a final target shape. At this time, in the finish machining, when the feed speed of the tool 3 is switched during machining, the machined surface roughness of the workpiece may change, and the appearance of the workpiece may change at the switching portion of the feed speed, which may cause a problem in appearance. In addition, when the machining path is assumed to be a broken line approximation, the movement direction vector of the tool 3 changes in the switching portion of the line segment of the machining path, and the streak appears as a machined surface of the workpiece 1, which may cause a problem in appearance. Therefore, it is sometimes undesirable to change the feeding speed and the machining path of the tool 3 on the machined surface during finishing.
Therefore, the conversion program 1411 according to the present embodiment makes the displacement of the workpiece 1 in the finishing performed later constant in the rotation axis direction with respect to the NC program for rough machining. Specifically, the conversion program 1411 determines the following processing path Pr (rough processing moving path) as shown in fig. 10 a: the cutting in rough machining is increased so as to reduce the amount of finish machining in the portion of the workpiece 1 where the rigidity is low, and the cutting in rough machining is reduced so as to relatively increase the amount of finish machining in the portion of the workpiece where the rigidity is high.
Here, the cutting force F during finishing can be modeled as a model proportional to the finishing amount a (=cutting in during finishing).
When the rigidity K in the finishing is used, the displacement δ in the finishing is represented by formula (3).
δ＝F/K…(3)
Here, since f_α, δ_α/K is set to be constant, if the finishing amount a is left in the rough machining so that a/K is constant, the displacement of the workpiece at each machining position in the finishing can be made constant.
Therefore, the conversion program 1411 generates a machining path Pr shown in fig. 10 (B) in which a finishing amount a is kept constant at each machining position in the NC program for rough machining.
In this way, if the displacement at the time of finish machining becomes constant, the deviation from the machining path in the NC program 1416 before correction may be set with respect to the machining path Pf of finish machining, so that no streaks remain on the machined surface. Thus, in finish machining, it is not necessary to change the feed speed and the machining path during machining, and high-precision machining can be realized.
In this embodiment, it is also possible to switch which of the processes for generating the NC program for roughing (the process for roughing) and the processes for generating the NC program in embodiments 1 to 3 (the normal process) is executed. Therefore, the conversion program 1411 determines whether to perform the rough processing, and executes either the rough processing or the normal processing based on the result thereof. In the determination of whether or not to perform the rough processing, for example, a comment indicating whether or not to perform the rough processing may be included in the NC program before correction, and the determination may be performed based on the comment. Further, the tool number or the tool offset number may be defined as a rough machining tool or a finish machining tool, and whether or not to perform the rough machining process may be determined based on whether or not the tool in the NC program before correction is a rough machining tool. Further, whether or not the NC program before correction is for roughing may be managed based on the number and the file name of the NC program, and whether or not to perform the roughing process may be determined based on the number and the file name of the NC program before correction of the object. In addition, the present embodiment is not limited to a combination of rough machining and finish machining, but may be applied to pre-machining (for example, semi-finish machining, intermediate machining, and rough machining) as machining before finish machining is performed. In this case, the content described as "rough processing" may be rewritten as "pre-processing".
< deformation >
The present invention is not limited to the above-described embodiments, and can be implemented by appropriately modifying the scope of the present invention without departing from the gist of the present invention. The processes described below may be used in combination.
For example, in the above-described embodiment 4, the radial displacement of the workpiece is made constant over the entire machining range in the rotation axis direction of the workpiece, but the present invention is not limited to this, and for example, the radial displacement of the workpiece may be made constant over a part of the machining range in the rotation axis direction of the workpiece, whereby the machining accuracy in a part of the machining range can be improved.
In the above embodiments, a part or all of the processing performed by the CPU11 may be performed by a hardware circuit. The program in the above embodiment may be installed from a program source. The program source may be a program distribution server or a nonvolatile storage medium (e.g., a removable storage medium).
In the above embodiments, the NC program generating system is configured by the conversion computer 10, but the NC program generating system may be configured by the control device 26 of the machine tool 2. That is, the control device 26 may be provided with the function of the conversion computer 10.
In this case, the NC program generating system may be configured by a plurality of computers, and the functions of the conversion computer 10 may be executed by the processors of the plurality of computers.
Claims (9)
1. An NC program generation system includes a processor for generating an NC program for turning a workpiece in a lathe,
the processor calculates displacements occurring in a workpiece of a processing object at a plurality of processing positions at the time of turning processing,
the processor receives shape information of the workpiece, mechanical material property information of the workpiece, and rigidity information of a fixed portion of the lathe to which the workpiece is fixed, the fixed portion being a spindle of the lathe and a fixing jig attached to the spindle,
the processor calculates a displacement occurring in the workpiece at the plurality of processing positions based on shape information of the workpiece, mechanical material property information of the workpiece, and rigidity information of the fixed portion,
the processor receives shape information of a tool used in the turning, mechanical material property information of the tool, and rigidity information of a tool fixing portion that fixes the tool to the lathe, calculates displacement occurring in the tool at the plurality of machining positions based on the shape information of the tool, the mechanical material property information of the tool, and the rigidity information of the tool fixing portion,
The processor determines a movement path of the tool at the time of the turning based on the displacement occurring in the workpiece at the plurality of machining positions and the displacement occurring in the tool, and generates an NC program for causing the tool to move in accordance with the determined movement path.
2. The NC program generating system according to claim 1, wherein,
the processor receives a pre-correction NC program that does not take into account displacement occurring in the workpiece during the turning for the turning of the workpiece, and generates the NC program by correcting a movement path of the tool during the turning in the pre-correction NC program based on the determined movement path.
3. The NC program generating system according to claim 1, wherein,
the processor determines a feed speed of the tool at the time of the turning process based on the displacement occurring in the workpiece and the displacement occurring in the tool at the plurality of processing positions, and generates an NC program for moving the tool at the determined feed speed.
4. The NC program generating system according to claim 1, wherein,
When the turning of the workpiece is performed as a pre-machining before finishing, the processor determines a pre-machining movement path of the tool, which is common to the workpiece in the finishing in a movement range including the plurality of machining positions, based on shape information of the workpiece and mechanical material property information of the workpiece, and generates an NC program for moving the tool along the pre-machining movement path.
5. The NC program generating system according to claim 1, wherein,
the processor receives angle information between a rotation axis of a fixing portion for fixing the workpiece to the lathe and a moving direction of the tool, and determines a moving path of the tool used in the turning based on displacement occurring in the workpiece at the plurality of machining positions and the angle information.
6. The NC program generating system according to claim 2, wherein,
the processor obtains an axial direction movement module, which is a module for moving the tool in an axial direction of a rotation shaft of a fixed portion for fixing the workpiece, from the NC program before correction, calculates a displacement occurring in the workpiece within a movement range of the axial direction movement module from shape information of the workpiece, mechanical material property information of the workpiece, and stiffness information of the fixed portion, and determines a correction movement path, which is a movement path for changing a radial movement position of the rotation shaft, from the calculated displacement, among the axial direction movement modules, and generates an NC program for moving the tool in accordance with the correction movement path.
7. The NC program generating system according to claim 6, wherein,
the processor divides a movement range of the axial movement module into a plurality of partial ranges, calculates displacement occurring in the workpiece in each of the partial ranges based on shape information of the workpiece, mechanical material property information of the workpiece, and rigidity information of the fixing portion, determines a correction movement path, which is a movement path that changes a movement position in a radial direction of the rotary shaft in the movement range of the axial movement module, based on the displacement in the plurality of partial ranges, and generates 1 or more modules of an NC program that causes the tool to move in accordance with the correction movement path.
8. An NC program generation method implemented by an NC program generation system that includes a processor and generates an NC program for turning a workpiece in a lathe,
calculate the displacement occurring in the workpiece of the processing object at a plurality of processing positions at the time of turning processing,
receiving shape information of the workpiece, mechanical material property information of the workpiece, and rigidity information of a fixing portion of the lathe for fixing the workpiece, the fixing portion being a main shaft of the lathe and a fixing jig attached to the main shaft,
Calculating displacement occurring in the workpiece at the plurality of processing positions based on shape information of the workpiece, mechanical material property information of the workpiece, and rigidity information of the fixed portion,
receiving shape information of a tool used in the turning, mechanical material property information of the tool, and rigidity information of a tool fixing portion for fixing the tool to the lathe,
calculating displacement occurring in the tool at the plurality of processing positions based on shape information of the tool, mechanical material property information of the tool, and rigidity information of the tool fixing portion,
determining a movement path of the tool at the time of the turning based on displacements occurring in the workpiece at the plurality of machining positions and displacements occurring in the tool,
an NC program for moving the tool according to the determined movement path is generated.
9. The NC program generation method according to claim 8, wherein,
receiving a pre-correction NC program which does not consider displacement generated in the workpiece during the turning for turning the workpiece,
the NC program is generated by correcting a movement path of the tool at the time of the turning in the NC program before the correction based on the determined movement path.
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| JP2019136459A JP7112375B2 (en) | 2019-07-24 | 2019-07-24 | NC program generation system and NC program generation method |
| PCT/JP2020/020805 WO2021014749A1 (en) | 2019-07-24 | 2020-05-26 | Nc program generation system and nc program generation method |
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| US12030148B2 (en) | 2024-07-09 |
| US20220258296A1 (en) | 2022-08-18 |
| WO2021014749A1 (en) | 2021-01-28 |
| CN113874799A (en) | 2021-12-31 |
| EP4006667A4 (en) | 2023-08-02 |
| JP2021022014A (en) | 2021-02-18 |
| EP4006667A1 (en) | 2022-06-01 |
| JP7112375B2 (en) | 2022-08-03 |
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